This chapter presents a discussion on the reliability theory of aging and longevity. In reliability theory, aging is defined as a phenomenon of increasing risk of failure with the passage of time (age). If the risk of failure is not increasing with age, then there is no aging in terms of reliability theory, even if the calendar age of a system is increasing. In terms of reliability theory, the dating problem of determining the system age is different from the performance assessment problem of a system's aging. In reliability theory, failure is defined as the event when a required function is terminated. Reliability of the system (or its component) refers to its ability to operate properly according to a specified standard. Reliability is described by the reliability function S(x), which is the probability that a system will carry out its mission through time x. The reliability function or survival function evaluated at time x is just the probability, P, that the failure time X is beyond time x, P. © 2005 Elsevier Inc. All rights reserved.
Gavrilov, L. A., & Gavrilova, N. S. (2005). Reliability Theory of Aging and Longevity. In Handbook of the Biology of Aging (pp. 3–42). Elsevier Inc. https://doi.org/10.1016/B978-012088387-5/50004-2